Hand-held optical triangulation position-determining instrument

ABSTRACT

A self-contained, hand-held instrument for determining geographic position in terms of the compass bearing to a first landmark, and the horizontal angle between the bearings to the first and a second landmark, comprises a frame, proximal and distal sighting indices, a first mirror adjacent the distal index and a seond mirror rotatable about a vertical and a horizontal axis for presenting an image of the second landmark in the first mirror, the first landmark is sighted over the top of the first mirror. Means are provided to read the angle of the second mirror. A compass has a casing which is rotatably mounted in the frame. An index and a pointer are mounted on the casing. Mirror means are provided for presenting an image of the compass index and graduations near the area of the first mirror. The compass pointer is long compared to the radius of the compass graduation circle.

States Patent 1 1 Messier et al.

[ HAND-HELD OPTICAL TRIANGULATION POSITION-DETERMINING INSTRUMENT Filed: Oct. 21, 1971 Appl. No.: 191,362

[ Sept. 11, 1973 [5 7 ABSTRACT A self-contained, hand-held instrument for determining geographic position in terms of the compass bearing to a first landmark, and the horizontal angle between the bearings to the first and a second landmark, comprises a frame, proximal and distal sighting indices, a first mirror adjacent the distal index and a seond mirror rotatable about a vertical and a horizontal axis for presenting an image of the second landmark in the first mirror, the first landmark is sighted over the top of the first mirror. Means are provided to read the angle of the second mirror.

A compass has a casing which is rotatably mounted in the frame. An index and a pointer are mounted on the casing. Mirror means are provided for presenting an image of the compass index and graduations near the area of the first mirror. The compass pointer is long compared to the radius of the compass graduation circle.

6 Claims, 8 Drawing Figures [52] US. Cl 356/145, 356/255, 33/272, 33/276 [51] int. Cl GOlc l/UO [58] Field of Search 356/138, 140, 142, 356/144, 145, 253, 255; 33/272, 277

[56] References Cited UNITED STATES PATENTS 2,953,060 9/1960 Carbonara.... 356/144 3,031,913 5/1962 Janeska 356/144 3,184,854 5/1965 Grasse 33/272 Primary Examiner-Ronald L/Wibert Assistant Examiner-Paul K. Godwin Attorney-James R. Head et al.

7'0 /Z\A I 46 4 a A 4 BACKGROUND OF THE INVENTION 1. Field of the Invention A This invention lies in the field of positioning and surveying instruments in general. More specifically, it refers to an instrument which is adapted to determine the angular position of two distant landmarks by the use of mirrors, one of which is rotatable about a vertical axis.

More specifically it involves a small hand-held selfcontained instrument for use by fishermen for determining their position with respect to specific landmarks on shore, so that at some later time they can reoccupy the same position. t

2. Description of the Prior Art There is considerable prior art, in the general surveying area, of instruments for measuring the horizontal angle between two displaced lines of sight and for determining the compass bearing of a given line of sight.

There are also small instruments designed to provide both of these features in a single hand-held device. However, most of these are designed primarily for measuring angles in a horizontal plane and cannot adapt themselves to the measurement of position with a respect to two distant landmarks where said landmards are not in the same horizontal plane. Furthermore, these prior art instruments are limited in precision due to the very small radius of the compass reading circle.

SUMMARY OF THE INVENTION The weaknesses and disadvantages of the prior art instruments are overcome and the objectives of this invention are provided, by an instrument in which there is a frame, a sighting means including a first and second vertical index by means of which the instrument can be aligned with a distant landmark, a first and second mirror are provided, the latter being rotatable about a vertical axis. Thus the eye can see simultaneously the first landmark over the top of the first mirror, and an image of the second landmark in the first mirror, both of which can be aligned with the vertical indices. A compass is provided which can be read by means of a third and fourth mirror, the third mirror being positioned closely adjacent to the first mirror so that at a single BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents schematically the basis on whigh the instrument operates, showing the compass bearing to a first landmark and the angle between the compass bearings to a first and a second landmark.

FIG. 2 represents a plan view of the instrument ready for operation. FIGS. 2A and 28 represent views taken along lines A-A and B-B of FIG. 2.

FIG. 3 represents an elevation view of the instrument taken along line 3-3 of FIG. 2.

FIG. 4 is a representation of the field of view exposed to the user containing an object space, an image space,- a vertical direction reference, and a view of the compass, taken along line 4--4 of FIG. 2.

FIG. 5 shows a second embodiment of the instrument, and

FIG. 6 is a view taken along line 6-6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and in particular to FIG. 1, a'schematic diagram is shown in which a body of water 10 is surrounded by land on which there are two landmards l2 and 14. The instrument is held in a horizontal position at point 16 and the compass bearing of the first landmark 12 is angle a west of north. At the same time, the compass bearing of landmark 14 is -y east of north, making the total included angle between the two lines of sight B ='a+ y The geometry of the situation is such that, if at any future time the compass bearing of landmark 12 is a'west of north and the included angle between the two lines of sight is B then the instrument will be at position 16.

In order to reoccupy point 16 all'that is required is to follow a compass course in the direction of landmark 12 at a compass bearing of north or west. At position 13 the anglefl' between the compass bearing 27 to landmark 12 and the compass bearing 21 to landmark 14 is measured. If this angle 3 is less than the angle B originally measured, it indicates that the position 13 is farther away from landmark 12 than was'position 16. On the other hand, consider position 25, where thelangle )8" between the bearing directions 17 and 23 will be viewing the eye of theuser can see the two distant landmards in relation to the vertical indices,and the readvide information relative to the precise georgraphic position of the instrument at any time, so that at some future time that position can be reoccupied, based solely on the indication of the line of sight to a first landmark,

the angle of a second mirror and the reading of the compass bearing.

These and other objects of the invention andan un-' derstanding of the details and principles of the invention will become evident from the following description, taken in conjunction with the appended drawings, in which:

. FIG. 2 shows a plan view of the instrument larger than the previously measured bearing angle 3.

On the basis of whether thebearing angle is measured is greater or less than B, the user can determine whether he is farther from or closer to the landmark 12 than the original position 16. This illustrates the'basis upon which this instrument works. 7

ready for use, while FIG. 3' shows an'elevation view taken from the eye end of the instrument. In general, the instrument comprises a box having a left side wall 28, a bottom 24, a hinged top 32 attached to the side wall 28, and another side wall 34, which is fastened to the top, so that when the top is folded over, or hingedly rotated. clockwise; the entire instrument will be enclosed in the top, bottom, and two sides. There arealso two ends, 40 the eye and 42 the distal end, which are mounted to the bottom portion. For convenience, the instrument will be described in terms of a"left portion" of the instrument comprising the parts which are mounted on the top, and a "right portion of the instrument which are comprised of parts mounted on the bottom or on the intermediate deck 26 spaced up from the bottom. At the eye and 40, of the instrument there is an eye piece 36 comprising a small upright wall with a slot 33 representing vertical index, a circular opening, an eyepiece, or the equivalent. On the distal end of the instrument, corresponding to the end wall 42, in the left portion, is a vertical wire 46 or the equivalent, representing a second alignment vertical index. Sighting between the index 38 and the index 46, the instrument can be precisely aligned between the eye of the user and the selected distant landmark.

There is a rectangular mirror 44 mounted on the top plate adjacent the distal index 46. There is also a smaller mirror 48 which is mounted to the top plate in the lower left-hand corner of the mirror 48, but at a different angle. The index 46 preferably can extend up above the top of the mirror 48 so that in sighting a distant landmark the landmark is positioned above the top of the mirror in relation to the vertical index.

There is a second mirror 50 which is attached to a vertical rod 52 which is joumaled in the deck 26 and the base 24 of the right portion of the instrument (FIG. 2B) so that the mirror can be rotated according to the arrow 51 in a direction around the axis 52. This mirror carries a long pointer 56 or the equivalent which can be read against a circle and index lines 58.

Also, means are porvided for positioning a sheet of paper or a card 57 so that for each angle of the mirror 50 a line can be drawn on the card corresponding to the edge of the pointer 56. In this way, at some future time, the mirror 50 can easily be repositioned to that precise angle. By looking through the index 38 against the first mirror 44, the line of sight is directed to the mirror 50 and off the mirror 50 in accordance with beam 53 to the distant object or landmark 14.

The observer sees in the mirror 44 an image of the landmark 14. By adjusting the angle of the mirror 50 the region around the landmark 14 can be swept and the landmark positioned precisely with respect to the index 46 at the same time that the distant landmark 12 is sighted, with respect to the index 46, over the top of the mirror 44. The angle read against the circle 58 of the pointer 56 is a meausre of the angle between the sightlines 51 to the landmark 12, and 53 to the landmark 14. By resetting to that same angle at any future time from that same position 16, the two images should be lined up precisely against the index 46.

In FIG. 2B is shown the mirror 50, the vertical axis 52, and a horizontal axis-54 attahced permanently to the vertical axis 52, and about which the mirror 50 is adapted to rotate. Thus, if the landmark 14 is not in the same horizontal plane as the landmark 12, it is possible by adjusting this vertical angle of the mirror 50 to bring the two landmarks into juxtaposition as described above. 6 I

There is a compass 60 mounted so that the compass casing 62 is free to turn in a opening in the deck 26. There is an index line 64 mounted on the casing of the compass, against which the compass graduations 76 can be read. There is also a handle 66 hingedly mounted on the casing at hinge 67, so that it can be rotated inward when not in use and turned outward for operation. The handle 66 now permits the operator to rotate the casing of the compass so that the index 64 is precisely aligned with one of the graduations on the angle. The pointer would be on this mark when the index 64 lies opposite a graduation on the compass circle. If a compass graduation deviates from the index 64 by a fraction of a space between graduations (which on a small compass circle might be as large as 15) it becomes necessary to estimate the angle by interpolating the position of the index 64 between the two adjacent compass graduations.

However, by turning the compass case so that the index 64 falls directly on one, or the other, of the adjacent graduation marks on the compass circle the pointer will deviate from the zero mark on the circle 70, to an adjacent one. Since the diameter of the circle 70 can be several times as large as the diameter of the compass circle, the indices can be put closer together and will represent smaller angles, such as even one degree. Thus, interpolation is not required and compass bearings can be read more precisely.

This feature of expanding the diameter of the compass circle for purposes of higher precision in reading bearing angles is an important feature of this invention.

An example of the way this feature can be used is as follows: Assume that the position of the case is such that the index 64 is opposite a first graduation and the pointer is on a line A, on circle 70. Now if the case is turned to the adjacent second graduation on the compass the pointer will be on a line B on the circle 70. Assume that there are 15 lines between A and B, and 15' between the first and second graduations. Thus each line on the circle 70 corresponds to one degree on the compass.

If the index is positioned half way between the two graduations then the pointer 68 will be half way between A and B, or 7 1% degrees from A or B.

In use, if the index is between two graduations, it can be moved to the nearest one, and the movement of pointer 48 will indicateby the number of lines which it traverses, the angle on the compass circle through which the index has been moved. This number of degrees has been added to the reading corresponding to the graduation on which the index has been positioned. This is an innovation which permits, in efiect, magnifying a postion of the compass circle so that the portion of the scale between two adjacent graduations can be spread out over a large plurality of individual lines so that the reading of the compass can be more precise.

The third mirror 48 cooperates with a fourth mirror 72 positioned near the compass so that/an image of the compass corcle with its graduations and the index 64 can be seen in mirror 48 adjacent the mirror 44. FIG. 2A shows an elevation view of the mirrors 44 and 48 and index 46, taken along line A-A of FIG. 2.

Reference is now made to FIG. 4 wherein the numeral represents the field of view of the instrument as seen from the sighting index 38. The upper portion 82 of the field is clear space, in which the distant landmark 12 is seen. The line 46 represents the forward distal index 46. The lower half of the field of view indicated by numeral 84 is an image of the landmark 14. The small area marked 86 is an image formed by mirror 72, of the compass circle and the index 64.

This instrument permits an operator to adjust the angle of view in such a way that he can simultaneously view a first landmark and a second landmark against a common index, and also simultaneously view the compass circle graduation against a fixed index, indicating the compass bearing to the first landmark.

After the instrument has been used, the cover is rotated clockwise, so that parts 36, 48, 44 and 46 are enclosed in the right portion, and the entire instrument is enclosed.

Shown in FIG. 5 is a second embodiment of this invention. It comprises a base portion 100 and a top portion or arm 102 which can be conveniently molded in plastic or similar material. The arm 102 is pivoted about the base portion by means of a screw 104, tying the two parts together. There is a drilled hole that goes through the arm and the base portion, by means of which a rod 11 i can be pressed into the drilled opening to lock the arm and the base precisely to a selected angle.

As slender rod or wire 1 12 is fitted into a drilled hole,

at the eye end of the base portion, a mirror 108 is fastened to a bracket which is held in position by the rod 111 as it is pressed into the drilled hole 110. This mirror has a thin scribed line 114, which serves as an index line, so that by lining up the sight from rod 112 to line 1 14 the instrument can be sighted to a distant landmark 12 as seen over the top of the mirro 108. At the same time the line of sight 120 from the rod 112 goes to the scribed index line 114 on mirror 108 and is reflected back as line 121 to a second mirror 116 from which it is reflected as line 124 to landmark 14. The mirror 116 is mounted on a vertical rod 118, which fits into a drilled hole in the base, in such a manner that the mirror 116 can be rotated in the direction of the arrow 1 l7.

By rotating the mirror 116 to the position shown, the line of sight goes from mirror 108 to mirror 116 and to landmark 14 along line of sights 124. The landmark 14 can be sighted just over the top of the arm 102. Thus, at one time, the observer can sight the landmark 12 over the scribe line 114 and at the same time see the landmark 14 in the field of view of mirror 108.

As the line of sight 124 crosses over the arm 102, the scale 126, which is mounted on the edge 128, of the arm 102 is also visible, and the graduations can be read. Each of the numbered graduations is indicative of a specific angle B between the line of sight 120 to landmark 12, and the line of sight 124 to landmark 14.

By the means so far described, the operator is able to measure the horizontal angle between the lines of sight, or compass bearings, between two landmarks 12 and 14. There is a compass 60 with casing 62 positioned in a circular opening in the base 100 and mounted so that its casing 62 can be rotated. There is a pointer 12, graduated circle 130 and index 132 by means of which the case angle can be meausred and an index 126 against which the compass graduations can be read. This is provided, as in the case of FIG. 2, to avoid having to interpolate between the widely spaced graduations of the compass, which may be one for each 15 for example, as in the case of the instrument of FIG. 2. it is possible to rotate the casing 62 until the index 126 falls directly on one of the graduations, and by noting the reading on scale 130, opposite the index 132 it is possible to read the precise angular bearing of the compassin relation to the sightline to landmark 12.

There are four depressions in the top surface of the 'base portion, 134, 136, 138 and 140. These hold respectively shaft 118 with the mirror 116 occupying the dashed position 144, the rod 112 which fits into the slender cavity 136, the mirror 108 has a bracket which fits into the slot 140, the mirror itself occupying the space shown by dashed line 142 on top of the base 100, and the rod 111 fits into the curved shape depression 138. Everything is sealed below the surface of the base except the mirror 116, the mirror 108, and the compass. Corresponding clearances are provided in the underside of the arm 102 so that the arm can be rotated until it is directly over the base and by its presence protects and locks in position all of the parts hidden between the base and the arm.

While the invention has been described with a certain degree of particularity, it is manifest that may changes may be made in the details of construction and the arrangement of components. It is understood that the invention is not to be limited to the specific embodiments set forth herein by way of exemplifying the invention, but the invention is to be limited only by the scope of the attached claim or claims, including the full range of equivalency to which each element or step thereof is entitled.

What is claimed:

1. A self-contained, hand-held, position-determining instrument for recording the position of the instrument in terms of the compass bearing to a first landmark, and the horizontal angle between the bearings to said first and a second landmark, comprising:

a. frame means;

b. a first directional index at a first end of said frame, and a second directional index at the second end of said frame to permit orientation of said instrument in the direction of said first landmark;

c. first mirror means near said second directional index for imaging a second landmark in relation to said first landmark;

d. second mirror means intermediate the ends of said frame, rotatable about a vertical axis, to image said second landmark on said first mirror, and means for indicating a function of the relative angles of said first and second mirror means;

e. a compass with casing rotatably mounted to said frame, means to rotate said casing, index means on said casing, pointer means attached to said casing and means on said frame for indicating the angle of said pointer means; and

f. means to display a portion'of the compass graduations and compass casing index so as to be visible in the general direction of said first mirror, whereby the eye of the operator can simulta neously see the first landmark over the top of said first mirror, the second landmark insaid first mirror, and said compass graduations and casing index.

2. The position-determing instrument as in claim 1 in which said meansto display comprises a third mirror near said first mirror means and a fourth mirror mounted near said first end of said frame whereby said compass graduations and index are imaged by said fourth mirror onto said third mirror so as to be visible in the genreal direction of said first mirror.

3. The position-determining instrument as in claim 2 in which said frame comprises two portions hinged together, said first and second directional indices, said first mirror means, and said third mirror being mounted on a first portion, and said compass, said secondmirror means and said fourth mirror being mounted on the second portion.

4. The position-determining instrument as in claim 1 in which said second mirror means is additionally rotatable about a horizontal axis, whereby said second mirprises pointer means. can Image on Said first mm'or the Image of a second 6. The position-determining instrument as in claim landmark which is in a different horizontal plane than said first landmark.

5. The position-determining instrument as in claim 1 5 in which said means for indicating a function of the relof Said P ative angles of said first and second mirror means comincluding removable sheet means under said pointer on which a line can be drawn corresponding to one edge 

1. A self-contained, hand-held, position-determining instrument for recording the position of the instrument in terms of the compass bearing to a first landmark, and the horizontal angle between the bearings to said first and a second landmark, comprising: a. frame means; b. a first directional index at a first end of said frame, and a second directional index at the second end of said frame to permit orientation of said instrument in the direction of said first landmark; c. first mirror means near said second directional index for imaging a second landmark in relation to said first landmark; d. second mirror means intermediate the ends of said frame, rotatable about a vertical axis, to image said second landmark on said first mirror, and means for indicating a function of the relative angles of said first and second mirror means; e. a compass with casing rotatably mounted to said frame, means to rotate said casing, index means on said casing, pointer means attached to said casing and means on said frame for indicating the angle of said pointer means; and f. means to display a portion of the compass graduations and compass casing index so as to be visible in the general direction of said first mirror, whereby the eye of the operator can simultaneously see the first landmark over the top of said first mirror, the second landmark in said first mirror, and said compass graduations and casing index.
 2. The position-determing instrument as in claim 1 in which said means to display comprises a third mirror near said first mirror means and a fourth mirror mounted near said first end of said frame whereby said compass graduations and index are imaged by said fourth mirror onto said third mirror so as to be visible in the genreal direction of said first mirror.
 3. The position-determining instrument as in claim 2 in which said frame comprises two portions hinged together, said first and second directional indices, said first mirror means, and said third mirror being mounted on a first portion, and said compass, said second mirror means and said fourth mirror being mounted on the second portion.
 4. The position-determining instrument as in claim 1 in which said second mirror means is additionally rotatable about a horizontal axis, whereby said second mirror can image on said first mirror the image of a second landmark which is in a different horizontal plane than said first landmark.
 5. The position-determining instrument as in claim 1 in which said means for indicating a function of the relative angles of said first and second mirror means comprises pointer means.
 6. The position-determining instrument as in claim 5 including removable sheet means under said pointer on which a line can be drawn corresponding to one edge of said pointer. 